title: Enzyme-free and ultrasensitive electrochemical detection of nucleic acids by target catalyzed hairpin assembly followed with hybridization chain reaction.
abstract: An isothermal, enzyme-free and ultrasensitive protocol for electrochemical detection of DNA is proposed based on the ingenious combination of target catalyzed hairpin assembly and hybridization chain reaction (HCR) strategies for two-step signal amplification. The DNA hairpin assembly on the electrode is triggered by target DNA, accompanied by the release of target DNA for the successive hybridization and assembly process. The newly emerging DNA fragment on the electrode after hairpin assembly is further used to propagate the HCR between methylene blue-labeled signal probe and auxiliary probe, inducing a remarkably amplified electrochemical signal. The current dual signal amplification strategy is relatively simple and inexpensive owing to avoid the use of any kind of enzyme or sophisticated equipment. It can achieve a sensitivity of 0.1 fM with a wide linear dynamic range from 1 × 10(-15) to 1 × 10(-10)M and discriminate mismatched DNA from perfect matched target DNA with a high selectivity. The high sensitivity and selectivity make this method a great potential for early diagnosis in gene-related diseases.
authors.affiliation: College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, People's Republic of China.
authors.forename: Shufeng
authors.initials: S
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Ming
authors.forename: Ying
authors.initials: Y
authors.lastname: Lin
authors.forename: Chuanbin
authors.initials: C
authors.lastname: Cheng
authors.forename: Feng
authors.initials: F
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D009693:Nucleic Acid Hybridization / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D004247:DNA
keywords: DNA hybridization; Electrochemical biosensor; Hybridization chain reaction; Target catalyzed hairpin assembly; Two-step signal amplification